During various medical catheterization procedures, such as cardiac catheterization, central venous catheterization for parenteral nutrition, arterial catheterization, etc., there is a severe danger of a fatal air embolism and/or uncontrolled hemorrhaging. Such serious consequences can occur during the process of catheter insertion when the syringe is removed in order to thread the catheter, or during tubing changes, or if the intravenous tubing becomes inadvertently detached from the intravenous catheter, or after the catheter has been withdrawn and before the tract seals.
Attempts to prevent inadvertent separation of the tubing have included taping the components together or physically forcing them into one another; however, these attempts have not solved the problem and, in fact, sometimes result in air leaks by fracturing the hubs. In addition, certain safety valve arrangements have been attempted, such as those described in U.S. Pat. Nos. 2,693,801 (Foreman); 3,105,511 (Murphy); 3,399,677 (Gould et al); and 3,570,484 (Steer et al). In each of these devices the mechanism which actuates valve closure to provide the safety feature is disposed in the flow path of the administered fluid. Any tendency of the fluid to agglomerate on the mechanism compromises the safety feature. Moreover, such valves as disclosed in the aforementioned references, tend to be sufficiently complex and expensive as to render them less than ideal for disposability after use in a single procedure; lack of disposability, on the other hand, requires that the valve be cleaned and resterilized before each use. Further, it is questionable as to whether or not the valves in the aformentioned patents are sufficiently fast-operating to preclude a sudden explosive burst of air from entering the patient's vascular system during the valve closure interval.